Conventionally, polymerizable monomers which have a perfluoroalkyl group in a side chain, such as fluorine-containing alkyl ester of acrylic acid and a fluorine-containing alkyl ester of methacrylic acid, are widely known as a fluorine compound which can be cured by radiation of light, such as ultraviolet ray. As a typical example, acrylate which has the following structure has widely been used in order to provide a substrate surface with water- and oil-repellency, stain resistance, abrasion resistance, and scratch resistance.

However, recently, there is an increasing tendency with environmental concerns to regulate use of compounds which have a long-chain perfluoroalkyl group having eight or more carbon atoms. Meanwhile, it is known that acrylic compounds having a perfluoroalkyl group with less than eight carbon atoms give worse surface property than ones having a perfluoroalkyl group with eight or more carbon atoms do (non-patent literature 1).
Meanwhile, photo-curable fluorine compounds are known which have a perfluoropolyether group composed of an oxygen atom participating in an ether bond and a perfluoroalkyl group having three or less adjoining carbon atoms. For instance, patent literature 1 discloses the following acrylic compound which is derived from a hexafluoropropylene oxide oligomer.

Patent literature 2 discloses a urethane acrylate which is a reaction product of a fluorine-containing polyether diol with 2-isocyanatoethyl methacrylate. However, this fluorine compound has bad compatibility with photo polymerization initiators, non-fluorinated acrylates, and non-fluorinated organic solvents due to its water- and oil-repellency and, therefore, can be blended with restricted number of components and has restricted usage.    [Non-patent literature 1]: Koubunshi Ronbun-Shu Vol. 64, No. 4, pp 181-190 (April, 2007).    [Patent literature 1]: Japanese Patent Application Laid-Open No. Hei-5-194322    [Patent literature 2]: Japanese Patent Application Laid-Open No. Hei-11-349651